Dr. David Bailey from the University of Western Ontario in London, Canada, reported the “grapefruit effect” more than 15 years ago.

Now, Dr. Bailey and coworkers at the University of Western Ontario tell us that while 17 drugs were identified in 2008 as having the potential to cause serious problems when taken with grapefruit, this number has now grown to 43. (more…)

Berberine is used to treat gastrointestinal infections, diabetes, high blood pressure, and cholesterol. Many studies report interactions between berberine-containing products and cytochrome P450, but little is known about whether berberine alters CYP activities in humans.

Researchers at the Xiang Ya School of Medicine, in the People’s Republic of China, studied the effects of berberine on a series of drugs and P450 enzymes after repeated dosing. (more…)

Researchers at Tufts University School of Medicine and Tufts Medical Center, in Boston, are the first to evaluate changes in the cholesterol-lowering effects of atorvastatin (Lipitor) in patients with high cholesterol taking stable doses atorvastatin while drinking typical quantities of grapefruit juice. (more…)

Researchers in the US reviewed the incidence and severity of potential interactions between prescription medicine and dietary supplements. (more…)

Tolvaptan (Samsca) is used to treat hyponatremia — too little sodium in the blood.

Patients with heart failure, liver problems (eg, cirrhosis), and the syndrome of inappropriate antidiuretic hormone (SIADH) may have hyponatremia. (more…)

Researchers from the Cheyenne Veterans Affairs Medical Center, in Wyoming report that when taken together, 1 patient experienced bleeding from the blood “thinner” warfarin (Coumadin). (more…)

It’s a long list compiled by researchers at RMIT University in Victoria, Australia. (more…)

During the American Heart Association meeting, Dr. Jennifer Strohecker, at the Intermountain Medical Center, in Salt Lake City, Utah, reported that documentation of supplement use in the medical chart is poor. (more…)

Not much, according to researchers in Spain. (more…)

“The warning that there is a potential to enhance the effect of warfarin… with cranberry juice intake is mostly based on faulty reports.”

That’s the conclusion by researchers at Lenox Hill Hospital, in New York City. (more…)

Ask about the grapefruit/drug interaction and most people think of the increased blood levels of statins when grapefruit is eaten before taking a dose.

Now, Dr. David Bailey at the University of Western Ontario, in London, Ontario, has reviewed fruit juice interactions that result in lower drug blood levels. (more…)

Real and hypothetical concerns exist.

Dr. Mark Moyad (photo), who is Director of Preventive and Alternative Medicine at the University of Michigan Medical Center in Ann Arbor, puts it into perspective. (more…)

Aliskiren (Tekturna) is used to treat high blood pressure. It’s poorly absorbed from the intestines (about 2.5%).

Researchers at Helsinki University Central Hospital, in Finland, report that apple and orange juice further reduce the amount that gets absorbed from the intestines. (more…)

Shengmai-yin (Sheng Mai Yin Pian) is a concentrated Chinese herbal medicine used to “treat a deficiency of vital energy and Yin, palpitation and shortness of breath, faint pulse, and spontaneous perspiration,” according to ActiveHerb.com.

Researchers at Zhejiang University, in Hangzhou, China report a patient who appeared to suffer from an interaction with warfarin (Coumadin). (more…)

It’s suggested that honey may stimulate the CYP3A enzyme, and this might alter the metabolism of drugs.

Researchers in Germany studied the effect of repeated honey administration on human CYP3A enzyme activity using the benzodiazepine drug midazolam (Versed). (more…)

Researchers at Central South University, in Hunan, China studied the effect of curcumin (turmeric) on drug metabolizing enzymes.

Their findings suggest a risk for curcumin-drug interactions. (more…)

The U.S. Government Accountability Office (GAO) presented to congress the results of a “secret shopper” investigation, which found that in some stores, salespeople made inappropriate or illegal claims about dietary supplements.

What to do? (more…)

Researchers from the Mayo Clinic, in Rochester, Minnesota have listed drugs to avoid when taking tamoxifen (Nolvadex) to treat breast cancer, but they omit reference to herbal supplements.

A study from the University of Arkansas helps correct their oversight. (more…)

Researchers from Kyung Hee University in Seoul, Republic of Korea studied Asian ginseng (Panax ginseng) and found no interaction with the blood thinner, warfarin (Coumadin). (more…)

Losartan (Cozaar), which is used to treat high blood pressure, is metabolized by liver enzymes CYP2C9 and CYP3A4 to an active metabolite, E-3174, which has greater antihypertensive activity than Losartan itself.

We also know that soy extract activates CYP2C9 and CYP3A4 in the lab. Should we worry about a soy-drug interaction? (more…)